Penis and scrotum - Melanosis and lentiginosis

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Penis and scrotum

Inflammatory lesions

Melanosis and lentiginosis

Reviewers: Antonio Cubilla, M.D. and Alcides Chaux, M.D. (see Author/Reviewers page)

Revised: 19 February 2010, last major update February 2010

Definition

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● Penile melanosis and penile lentiginosis are benign pigmented lesions frequently found in glans and foreskin

● Penile melanosis shares clinicopathological features with Laugier-Hunziker syndrome of oral mucosa (eMedicine) and vulvovaginal melanosis (J Am Acad Dermatol 1989;20:567)

Clinical features

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● Benign, although associated with melanoma

Penile melanosis:

● Large, often single, flat, pigmented macule with irregular borders

● Pigmentation may be associated with Laugier-Hunziker syndrome (Int J Dermatol 2004;43:571)

Penile lentiginosis

● Penile lentigines are 0.2 to 2 cm, oval to irregular lesions with uniform or variegated pigmentation

● Areas of depigmentation are characteristic

● Lesions are scattered on shaft or glans

● Clinically may resemble an atypical melanocytic lesion

● May be associated with Cowden’s disease (J Cutan Med Surg 2001;5:228), Bannayan-Riley-Ruvalcaba syndrome (J Am Acad Dermatol 2005;53:639)

Clinical images

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Melanosis - irregular darkly pigmented patch on Lentiginosis - 4 cm, asymmetric,well demarcated

skin of shaft (Genital skin disorders, diagnosis patch of variegated pigmentation with irregular

and treatment, Mosby, 1998:73) borders

Micro description (Histopathology)

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Penile melanosis

● Melanocytic hyperplasia, hyperpigmentation of basal epithelium, otherwise normal epithelium

Penile lentiginosis

● Elongation of rete ridges with basal layer hyperpigmentation, slight melanocytic hyperplasia, epithelial hyperplasia and stromal melanophages, no atypia (J Am Acad Dermatol 1990;22:453)

● In hyperpigmented areas, there are increased number of melanocytes along the basal layer

● Lymphocytes, which are found in close apposition, destroy melanocytes, and surrounding keratinocytes lack pigmentation (Pigment Cell Res 1992;5:404)

Micro images

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Melanosis – hyperpigmentation of basal cell Lentiginosis - increased basilar hyperpigmentation,

layer with focal elongation of rete pegs occasional dermal melanophages; no

significant increase in melanocytes, no atypia

Differential Diagnosis

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● Congenital melanocytic nevus

● Melanoma: difficult to distinguish clinically, may need to biopsy (Urology 1976;7:323)

End of Penis and scrotum > Inflammatory Lesions > Melanosis and lentiginosis

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